Improvement in mechanical telephones



B. D. PINCH. Mechanical-Telephones.

No. 216,840. Patented June 24,1879.

WITNESSES; IVNVENTOR:

.M m h H69. dmpfi UNITED STATES PATENT OFFICE.

EDIVIN D. FINOH, OF STANTON, MICHIGAN.

IMPROVEMENT lN MECHANICAL TELEPHONES.

Specification forming part of Letters Patent No. 216,840, dated June 24,1879; application filed March 11, 1879.

To all whom it may concern:

Be it known that I, EDWIN D. FINOH, of Stan-ton, in the county ofMontcalm and State of Michigan, have invented a new and ImprovedMechanical Telephone, of which the following is a specification.

My improvements relate to mechanical telephones, wherein the vibrationsof a diaphragm are transmitted by a cord or wire to areceiving-diaphragm at a distance; and the invention consists in certainnovel features of construction whereby the vibrations are concentratedupon the line more perfectly than heretofore and false vibrationsprevented; also, in means for adjusting the tension of the line anddiaphragms, and relieving the diaphragms of tension when not in use.

In the accon'ipanying drawings, Figure 1 is a side elevation of myimproved telephone. Fig. 2 is a face view of the diaphragm and holder.

Similar letters of reference indicate corresponding parts.

In the drawings, a is the mouth-piece and diaphragnii-holder, which ismade in the form of a ring and sustained upon a stand, I).

c the diaphragm, which is made of silk, muslin, or other suitablematerial, and covers the central oriliee of holder (1.

Upon the face of the diaphragm c are ar ranged converging radial wires0, which are united together at the center of c, and clamped in holder aat the periphery of the diaphragm. These wires 0 are preferably of smalldiameter, and connect with lined by a hook-ended piece,

7, at a central aperture in 0, so that when the line is under tensionthe wires 0 lie closely upon and vibrate with diaphragm 0, but will notvibrate independently of c.

The action of the radial wires 0 is'to collect the vibrations of thediaphragm and concentrate them most perfectly upon the conductingline.The wires 0 are united as one wire at the center, where they connect tothe line.

By this construction false vibrations and sounds are 1 )revented, andthe roaring sound which usually accompanies conversation with telephonesis avoided. The diaphragm is also rendered much more sensitive to soundthan heretofore, and gives the natural tone and articulation moremrfectly.

The line between hookf and the main por tion consists of a chain, 9,that is attached to d and hooks upon f, whereby the tension of the linemay be increased or slackened by taking upon one or more links of thechain. The chain 9 also extends from its point of connection to (Z to ahook-stud, h, on stand I), or other fixed point, whereby when theportion of the chain that is connected is sufficiently slackened thetension of the line will be upon stud h and the diaphragm c relieved.

To facilitate unhooking the chain, a bar, '1 is attached upon (1 or thechain, which maybe grasped for drawing on the line and slacking thechain while it is being shifted.

This 0 nstruction permits transfer of the tension of the line from thediaphragm to the win diass, or vice versa, in a moment. The diaphragm 0may therefore be relieved of strain when not in use, or it maybe setwith just enough tension to respond to a call. The normal tension of theline may be also adjusted by the chain 7;.

I have discovered in the use of telephones that the results are muchmore perfect when the diaphragms at opposite ends of the line are ofdifferent material, say one of silk and the other of linen, or varyinsize, say a difference of one or two inches in diameter. The effect isto flatten the sounds and prevent echoes on the line, which I believe tobe due to the difference in the time and amplitude of the vibrations.

Having thus described my invention, I claim as new, and desire to secureby Letters Patent- 1. The wires 0, arranged on the outer face of thediaphragm 0, so as to converge toward the center of the same, where theyare united together and connected to the line 11, in combination withthe diaphragm 0, substantially as and for the purpose set forth.

2. The hook f and the chain g, in combination with the diaphragm c andthe line (1, sub stantially as and for the purpose set forth.

3. The chain g and the stud h, in combina tion with the line it and thediaphragm 0, sub-- stantially as and for the purpose set forth.

EDW IN DAVID FINGH.

Witnesses:

A. F. GARDNER, GEORGE Howonrn, J. M. FULLER.

